Drill guide for combination lock mounting and method for using drill guide

ABSTRACT

A drill guide for combination lock mounting and method for fabricating andsing the drill guide is provided. The drill guide is fabricated using several interior mounting plates bonded together to form a sufficient thickness to maintain a true level bore hole. The fabrication guide plate is attached to a secure door using a threaded clamping device extending through a lock spindle hole. Thereafter, the smaller interior holes are drilled completely through the door. Larger exterior holes are then drilled partway through the door from the outside. The door is then ready to accept an exterior combination lock plate having female studs extending into the door.

ORIGIN OF THE INVENTION

The invention described herein was made in the performance of officialduties by an employee of the Department of the Navy and may bemanufactured, used, licensed by or for the Government for anygovernmental purpose without payment of any royalties thereon.

FIELD OF THE INVENTION

The invention described herein relates to cutting tools and inparticular to jigs and guides for drilling.

BACKGROUND OF THE INVENTION

The use of various guides including jigs and templates for the drillingof holes is well known in the art. A particularly challenging use ofthese guides is in the attachment of drill-proof exterior plates used onsafes and combination locks. These locks are mounted on a door from theinside with solid drill resistant plates on the outside. Often the solidexterior plate has female studs which extend only partway through thedoor. These configurations require the accurate location and trueleveling of all installation holes and typically require drilling fromboth the interior of the door and the exterior of the door. An exampleis a door requiring larger stud holes drilled from the exterior side ofthe door with smaller concentric holes (for attachment screws) drilledfrom the interior side of the door. All of these holes must be preciselylocated, precisely level, and for interior-exterior concentric holes,precisely centered. These requirements make the use of a simple templatedifficult as the template must be leveled by some outside means in orderto produce a true level bore hole. Where different diameter holes,concentric and intersecting, must be drilled from opposite sides of adoor, even complex jigs frequently result in out-of-alignment bores.What is needed is a system to provide a small diameter bore hole on oneside of a door and a large diameter bore hole on the opposite side ofthe door, both holes being precisely level and aligned precisely on thesame centers.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the invention to provide a drill guidefor boring holes for lock mounting plates which accurately locatemounting holes on both sides of a door.

It is another object of the invention to provide a drill guide whichaccurately levels all mounting holes.

It is yet another object of the invention to provide a drill guide whichfacilitates the locating of exterior and interior pairs of bore holes sothat each pair has common centers of the exterior and interior boreholes.

It is a further object of the invention to provide a drill guiderequiring only a single set-up after which all interior and exteriorholes may be bored.

The invention is a drill guide fabricated using drill-proof steel havinga thickness sufficient to provide a true level alignment of a drill bit.The guide is a rectangular fixture approximately 3"×5" and 3/4" thickhaving a one-half inch clamping hole and a plurality of smaller guideholes. The one-half-inch clamping hole is used with threaded clampswhich secure the guide to a door by clamping through the lock spindlehole. A typical installation is accomplished by removing the old lockand accurately positioning the drill guide over the old lock location.Thereafter, the drill guide is attached to the door using the two screwsnearest the strike plate. The threaded clamp is then used to completelysecure the drill guide. Once the drill is secured in position, smallbore holes are drilled from the interior of the door all the way throughthe door using the drill guide to provide hole location and boreleveling. The task is completed by drilling larger bore holes from theexterior side of the door, these holes centered on the smaller holesdrilled from the inside. The larger bore holes extend only partwaythrough the door as necessary to fit the exterior combination plate.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing objects and other advantages of the present invention willbe more fully understood from the following detailed description andreference to the appended drawings wherein corresponding referencecharacters indicate corresponding parts throughout the several views ofthe drawings and wherein:

FIG. 1 is a perspective view of the drill guide showing the generaldimension and hole locations.

FIG. 2 is a perspective view of the clamping device used to secure thedrill guide to a door.

FIG. 3 is a cross-sectional view of a door with the drill guide beingused to set the smaller interior holes.

FIG. 4 is a cross-sectional view of a door with the drill guide beingused to set the larger exterior holes.

FIG. 5 is a cross-sectional view of a door showing the installation of atypical combination lock.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1, the drill guide of the present invention,designated generally by the reference numeral 10, is shown depicting itsmajor features. The guide plate 12 is approximately 3"×5" and 3/4"thick. This thickness 14 is sufficient to provide a true alignment ofthe interior bore holes which are formed by drilling through guide holes17, 18 and 21, 23, 25 and 27. The larger hole 16 is aligned with thelock spindle location and is used for clamping the guide plate 12 to adoor. The drill guide 10 in the preferred embodiment was fabricatedusing drill-resistant steel interior plates from several locks. A seriesof these plates 19 were bonded together to provide sufficient thickness14 to maintain accurate level alignment of the drill bit. This drillguide 10 may be fabricated using other means providing the thickness issufficient to maintain drill alignment and the material is resistant toguide hole enlargement by the drill. Section III--III is shown in detailin FIG. 3.

Referring now to FIG. 2, the clamping device 20 is shown with itscomponents. The clamping device 20 has an attached hand-operated knob 24attached to a one-quarter-inch threaded rod 28. A second threadedhand-operated knob 29 is attached to the other end of the threaded rod28. At least one washer 26 is required to span the lock spindle openingon the door.

FIG. 3 depicts a cross-section of a typical secure door 4. The door 4typically has outer steel sheathing 6 which can be drilled. The drillguide 10 is also shown in cross-section, the guide 10 comprising theguide plate 12 and the clamping device 20. The guide plate 12 is securedto the door 4 by the clamping device 20 which, in this instance, isshown with the washers 26 on both sides of the door 4. For reference,the threaded rod 28 is shown with the attached knob 24 and the threadedknob 29. The guide holes 21 and 25 (on the striker plate side of theguide plates) are shown with the bore hole from guide hole 25 drilledcompletely through the door 4. The bore hole from guide hole 21 depictsthe completion of drilling by hand drill 8 using a small drill. In thepreferred embodiment, the holes drilled from the interior of the door,that is, the side of the door on which the drill guide 10 is mounted,are drilled using a 7/32" drill bit which is the exact fit for the guideholes in the guide plate 12.

Completion of the door 4 may be seen in FIG. 4. The hand drill 8 is usedto bore larger exterior holes 41 and 42. These holes are sunk to a depthless than the thickness of the door 4, but deep enough to accommodatefemale studs located on an external combination face plate. Bore hole 42shows a completed hole with a larger diameter exterior side and asmaller diameter interior side. These larger holes 41 and 42 arecompleted by boring directly into the center of the smaller holes whichhave been drilled from the inside of the door.

FIG. 5 shows a cross-section of the completion of the lock installationon door 4. The combination lock and exterior plate 100 slides into thedoor 4 as shown with the female studs 103 and 105 fitting into largebore holes 41 and 42, respectively. The interior side of the door has asteel sheathing 6 which has only the smaller interior holes 17 and 18.To finish the installation, the interior plate 101 is attached to theinterior of the door 4 using fasteners represented here as the bolts102.

The features and advantages of the invention are numerous. The priormethods require drilling by sight or template and then widening theholes repeatedly until the exterior mounting plate can be inserted andaligned with the interior mounting plate. Using the invention herein,the positioning and alignment of the bore holes is accurate on the firstdrilling. The larger exterior holes are also concentric and aligned onthe first drilling. As a result, the installation job is much quickerand much neater. Very little special equipment is needed. The drillguide plate can be fabricated on site using several interior platesbanded together.

Although the invention has been described relative to a specificembodiment thereof, there are numerous variations and modifications thatwill be readily apparent to those skilled in the art in the light of theabove teachings. It is therefore to be understood that, within the scopeof the appended claims, the invention may be practiced other than asspecifically described.

What is claimed as new and desired to be secured by Letters Patent ofthe united states is:
 1. A drill guide for mounting a combination lockto a door having a lock spindle bore, said drill guide comprising:aguide plate having a plurality of guide holes and a larger bore holebored therethrough, said plurality of guide holes being parallel to saidlarger bore hole and being distributed about said larger bore hole; anda clamping device inserted through said larger bore hole and a lockspindle bore of a door for attaching said guide plate to the door.
 2. Adrill guide for mounting a combination lock as in claim 1 wherein saiddrill guide is fabricated using drill-resistant steel plates.
 3. A drillguide for mounting a combination lock as in claim 1 wherein said guideplate comprises a plurality of plates bonded together to a thicknesssuch that each of said plurality of guide holes can maintain alignmentof a drill bit passing through one of said plurality of guide holes. 4.A drill guide for mounting a combination lock as in claim 1 wherein saidclamping device further comprises a threaded rod having a hand-operatedknob attached to a first end and a threaded knob attached to a secondend, such rod having at least one washer located thereon.
 5. A methodfor using a drill guide for mounting a combination lock to a door havinga lock spindle bore, said method comprising the steps of:fabricating aguide plate having a plurality of guide holes and a larger bore holebored therethrough, said plurality of guide holes being parallel to saidlarger bore hole and being distributed about said larger bore hole;fabricating a clamping device that cooperates with said larger bore holeand the lock spindle bore of a door for attaching said guide plate tothe door; clamping said guide plate to an interior side of a door usingsaid clamping device; drilling first holes from the interior side of thedoor completely through the door using said plurality of guide holes;drilling second holes partway through the door from an exterior sidethereof using said first holes as guides, wherein said second holes arelarger in diameter than said first holes; removing said guide plate;installing an exterior combination lock mounting plate from the exteriorside of the door using said second holes and the lock spindle bore; andsecuring an interior combination lock mounting plate from the interiorside of the door to said exterior combination lock mounting plate usingfasteners that project into said first holes.
 6. A method according toclaim 5 wherein said step of fabricating a guide plate comprises thestep of bonding together a plurality of drill-resistant plates to formsaid guide plate having a thickness that maintains alignment of a drillbit passing through one of said plurality of guide holes.